The present invention relates to methods of forming interdigitated back contact (IBC) layers that may be used in photovoltaic (PV) devices. IBC solar cells are the most efficient Si solar cells today. In IBC solar cells, both junctions that collect positive and negative photocarriers are on the back of the cell, while the front has no grid and thus no shading losses. However, the dopant patterning required for these back junctions is challenging. Heavily doped p-type and heavily doped n-type regions should be separated by a highly resistive gap that may be made of intrinsic polysilicon or another dielectric material, otherwise the cell may be shunted. Further, the doped regions should be several hundred microns wide with well-defined edges, in order not to shunt across the undoped gap. Thus, reliable, precise, and inexpensive dopant patterning is needed for IBC solar cells.
Related art dopant patterning techniques include ion implantation through a mask, plasma immersion ion implantation (PIII) through a mask, and printed spin-on doping. However, these techniques can be costly, and may not be clean enough to enable high-efficiency IBC solar cells. Therefore, it would be advantageous to provide a simple, inexpensive, and precise dopant pattering technique that is compatible with solar cell processing.